Quantification of aortic regurgitation using high-pulse repetition frequency three-dimensional colour Doppler

Abstract

The aim of this study was to validate and assess the feasibility of a previously described method using multibeam high-pulse repetition frequency (HPRF) colour Doppler to quantify the vena contracta area (VCA) in aortic regurgitation (AR). Twenty-nine patients with mild to severe AR were studied. Regurgitant volume and fraction measured by magnetic resonance imaging (MRI) were used as the standard of reference. The VCA was measured automatically by combining the Doppler power from multiple beams with a priori knowledge of the individual beam profiles, to give an absolute measurement of the VCA. The regurgitant volume was calculated as the product of the VCA and the velocity time integral, measured separately by continuous wave Doppler. The Spearman's rank correlation between regurgitant volume by MRI and multibeam HPRF colour Doppler was rs = 0.73 (P < 0.01), with 95% limits of agreement of -14.4 ± 29.1 mL. The mean difference between the methods in those with MRI regurgitant volume of ≥30 mL (n = 14) was -7.6 (95% confidence interval -13.9 to -1.2) mL. There was good agreement between MRI and multibeam HPRF colour Doppler in patients with moderate to severe AR, while agreement for those with mild AR was modest.